(a) Field of the Invention
The present invention relates to a thin film transistor (“TFT”) substrate and a manufacturing method thereof.
(b) Description of the Related Art
A liquid crystal display (“LCD”) is one of the most commonly used flat panel displays, and it includes two substrates with electrodes formed thereon and a liquid crystal layer interposed between the two substrates. In the LCD, a voltage is applied to the electrodes to align liquid crystal molecules of the liquid crystal layer to thereby regulate the transmittance of light passing through the liquid crystal layer.
Among the various types of LCDs, an LCD having a structure in which field generating electrodes are respectively formed on two display panels is widely used. Among the two display panels, a plurality of pixel electrodes and thin film transistors (“TFTs”) are arranged in a matrix format on one display panel (hereinafter referred to as “a TFT array panel”), and color filters of red, green, and blue are formed on the other display panel and one common electrode covers the entire surface of the other display panel (hereinafter referred to as “a common electrode panel”).
However, in this type of liquid crystal display, the pixel electrodes and the color filters are disposed on different display panels such that it is difficult to align the pixel electrodes and the color filters to each other, thereby generating an alignment error.
To solve this problem, a color filter on array (“CoA”) structure in which the pixel electrode and the color filter are formed on the same display panel is provided. Here, a light blocking member is generally formed on the same display panel as the pixel electrode as well as the color filter.
When forming the color filter on the same display panel as the pixel electrode, the color filter is formed through an Inkjet printing process, thereby reducing the manufacturing time and cost by simplifying the manufacturing process. The light blocking member is formed as a partition in the Inkjet printing method.
However, the partition of the light blocking member has a low height such that it is difficult to sufficiently divide the color filter formed by the Inkjet printing. Also, the partition of the light blocking member is tapered, but the taper angle is small such that it is difficult to stably enclose the color filter.
In the color filter on array (“CoA”) structure, a contact hole for electrically connecting the pixel electrode and the drain electrode is formed in the color filter, however the process is not easy. This is because the color filter or the black matrix between the pixel electrode and the drain electrode must be removed, and the removal may involve multiple precise steps.